1. Field of the Invention
The present invention relates to a photoelectrical conversion device made of non-single-crystal material and a generating system using the same.
More particularly, the present invention relates to a pin-type photoelectrical conversion device having an i-type layer, in which the band gap is changed, and a generating system using the same.
2. Related Background Art
Hithero, a variety of disclosures have been made about the structure of a pin-type photovoltaic device made of non-single-crystal silicon semiconductor material of a type have an i-layer containing silicon atoms and germanium atoms and including a changed band gap.
For example, the following suggestions have been made:
(1) "Optimum deposition conditions for a-(Si, Ge):H using a triode-configurated rf glow discharge system" J. A. Bragagnolo, P. Littlefield, A. Mastrovito and G. Storti, Conf. Rec. 19th IEEE Photovoltaic Specialist Conference-1987 pp. 878, PA1 (2) "Efficiency improvement in amorphous-SiGe:H solor cells and its application to tandem type solar cells" S. Yoshida, S. Yamanaka, M. Konagai and K. Takahashi, Conf. Rec. 19th IEEE Photovoltaic Specialists Conference-1987 pp. 1101, PA1 (3) "Stability and terrestrial application of a-Si tandem type solar cells", A. Hiroe, H. Yamagishi, H. Nishio, M. Kondo, and Y. Tawada, Conf. Rec. 19th IEEE Photovoltaic Specialists Conference-1987 pp. 1111, PA1 (4) "Preparation of high quality a-SiGe:H Films and its application to the high efficiency triple-junction amorphous solar cells" K. Sato, K. Kawabata, S. Terazono, H. Sasaki, M. Deguchi, T. Itagaki, H. Morikawa, M. Aiga and K. Fujikawa, Conf. Rec. 20th IEEE Photovoltaic Specialists Conference-1988 pp. 73, PA1 (5) U.S. Pat. No. 4,471,155, PA1 (6) U.S. Pat. No. 4,782,376, and PA1 (7) U.S. Pat. No. 4,816,082. PA1 (8) "A novel design for amorphous silicon alloy solar cells" S. Guha, J. Yang, A. Pawlikiewicz, T. Glatfelter, R. Ross, and S. R. Ovshinsky, Conf. Rec. 20th IEEE Photovoltaic Specialists Conference-1988 pp. 79, and PA1 (9) "Numerical modeling of multijunction, amorphous silicon based P-I-N solar cells" A. H. Pawlikiewicz and S. Guha, Conf. Rec. 20th IEEE photovoltaic Specialists Conference-1988 pp. 251.
Theoretical research of the characteristics of the photovoltaic device having the changed band gap are disclosed in:
The foregoing conventional photovoltaic device has a layer having a changed band gap and inserted therein in order to prevent recombination of photovoltaic carriers occurring in the vicinity of the interface between a p-layer and an i-layer and that between an n-layer and the i-layer, to raise the open voltage level and to improve the carrier range of the positive holes.
There is a desire to improve the degree of recombination of the photovoltaic carriers, the open voltage level and the carrier range of the positive hole of the conventional photovoltaic device of the type containing silicon atoms and germanium atoms and having the changed band gap as described above.
Further, the conventional photovoltaic device encounters a problem that the conversion efficiency deteriorates if the photovoltaic device is irradiated with weak light.
What is worse, the conventional photovoltaic device has a problem that the photoelectrical conversion efficiency deteriorates if the conventional photovoltaic device having a deformed i-layer is annealed in a place where vibrations take place.